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I have a problem. I have installed Windows 10 on /dev/sda1 and Ubuntu 14.04 on /dev/sda6. I use GRUB as bootloader but (I don't remember since when) when I choose Windows in the menu it does not boot and returns to GRUB.

I tried to reinstall GRUB but nothing worked so far. If I run sudo update-grub the system considers a Windows 7 bootloader and writes the menuentry. But why does it not boot?

UPDATE#1:

I followed your instructions cl-netbox and reinstalled GRUB as follows:

sudo mount /dev/sda7 /mnt
sudo mount -o bind /dev /mnt/dev
sudo mount -o bind /sys /mnt/sys
sudo mount -t proc /proc /mnt/proc
sudo cp /proc/mounts /mnt/etc/mtab
sudo chroot /mnt /bin/bash
grub-install /dev/sda
update grub

Now it does not return into GRUB after selecting Windows in bootmenu but Windows still does not boot. There is only a black screen showing _

Could that have something to do with the following message after executing?

bootrec.exe/scanos

Searching for Windows-installations was successful. Number of identified installations: 1 [1] C:\Windows.old\Windows (sorry for bad translation)

I have updated from Windows 7 to Windows 10

Zanna
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Phile Reinhardt
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1 Answers1

1

Maybe the Windows BCD store is corrupted.

To fix this boot from Windows install media.

On the "Install now" screen choose -> Repair your computer
In the System Recovery Options select -> Command Prompt

Execute the following commands: 

bootrec.exe /fixmbr  
bootrec.exe /fixboot  
bootrec.exe /scanos  
bootrec.exe /rebuildbcd

Shutdown the computer and boot from Ubuntu install media.
Reinstall GRUB and run the update-grub command afterwards.
Now you should be able to boot into Windows from GRUB menu.

A.B.
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cl-netbox
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